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How do LED light bulbs work?

How do LED light bulbs work?
(Image credit: Getty)

LED light bulbs offer an alternative to CFL and incandescent bulbs, but let’s start at the beginning. 

What does LED stand for? LED is an acronym for light-emitting diode and they are semiconductors. As electrons pass through this type of semiconductor, it turns into light. Compared to incandescent and CFL bulbs, LED lights are more efficient at turning energy into light.

If you're savvy about saving money and the environment, you've probably taken an interest in LED light bulbs because they're even more energy-efficient and environmentally safe than CFL and incandescent bulbs. 

To find more lighting inspiration, check out our guide to the best smart light bulbs.

Do LED light bulbs get hot?  

As LED light bulbs are better at turning energy into light rather than heat, they are cooler during operation than incandescent and CFL bulbs.

As the light-emitting diodes create light, they warm up quite a bit for their size. LEDs are heat sensitive, so it's important that the heat move away so that it doesn't damage the semiconductors. In order to do this, these lights need a system to keep cool. Most LED light bulbs have a heat sink plate that moves the heat away from the light-emitting diodes. Manufacturers make the heat sink plate out of a variety of materials, but it's commonly made from aluminum. Frequently, the heat sink becomes part of the design of the bulb.

An LED light bulb's heat sink usually weighs several ounces and can become hot once you turn on the light. From the heat sink plate, the heat moves into the air surrounding the bulb. 

Do LED light bulbs last longer? 

As LED light bulbs get older, they don't just burn out. Instead, they grow dimmer. Many LED light bulbs are expected to last up to 50,000 hours with at least 70% as much brightness as they have when they are new. Below 70% is the point at which the industry decided the decrease in brightness is noticeable.

Although most of these lights claim to last up to 10 years, their warranties only cover about three years. This is perhaps because if you run the LED lamp continuously, it will only stay within the 70% range for a little less than three years. However, if you look on the Lighting Facts label of many LED lamps, it gives a life based on years. This is because the industry standard is three hours of use per day instead of 24 hours.